Off-topic in this thread for installing Mavericks but briefly :
Made a USB installer with createinstallmedia.
Installed Clover on the USB.
Copied apfs.efi to the USB and the /EFI partition of the HDD.
Copied config.plist and kexts from the HDD to the USB.
Upgraded to the final release of High Sierra through the App Store on release day.
Hi bro I have an HP DC7900 WITH INTEL E8400 BUT I CANNOT BOOT UP TO INSTALL , so can you help me or send me the EFi you used for your HP and help me to fix ? I'm trying hard for 3 weeks to find a fix but no success help me Please !